With some minor modifications to port spacer dividers and driver brace, this design will also fit Alpair 7

Note if flush mounting the version of Alpair7 with extra thick bezel ring, the front baffle will need some adjustment as well - at almost 9mm thick, that doesn't leave a lot of meat for screws on a 15mm baffle.

But I'm sure it must be quite bass light? I remember using a Monacor SPH-30X in a ported box though (-6dB @ 72Hz, same as CHR-70 in sealed but with faster ported rolloff) and it giving a suprisingly full sound, so perhaps not? The hump in the response from using the CHR-70 in a smaller box is very minimal, is the capacitor really needed? I can't model its exact effect in WinISD. Nice to use a single polarity amplifier design with though!

It seems it could also squeeze into a fairly small ported box (7.7L) with a lower tuning point to give something of an EBS alignment (attached). The small hump from 100-200Hz shouldn't be an issue as the driver response around here is weaker compared to the 200-500Hz region. Still quite a large box though.

I think with a fullrange driver in particular it'd be desireable to use non-parallel walls, mabye curved sides and/or diffuson patterns on the inside?

A rectangular baffle can give a reasonably flat response with the driver carefully located (attached). The lift at 1KHz is broader than one would like (a high Q lift here would help balance the response nicely), but shouldn't upset it overall.

Any thoughts? Just throwing some ideas out while I consider these drivers!

With some minor modifications to port spacer dividers and driver brace, this design will also fit Alpair 7

Note if flush mounting the version of Alpair7 with extra thick bezel ring, the front baffle will need some adjustment as well - at almost 9mm thick, that doesn't leave a lot of meat for screws on a 15mm baffle.

A very complete set of plans will be available for a small cost once the beta testors have all reported back.

We have been planning on selling comprehensive plans (similar to what Bob Brines does), these are 1st because it is part of a commercial licencing agreement with a manufacturer in Denmark that is building the Alpair7 version as part of his commercial line.

The boxes for CHR70 and A7 are the same except for the details required of the different dimension drivers and slightly different porting. The plans will include both.

No. Mar-Kel is for the EL70, Mar-Ken is for the metal cone drivers. With no prefix, the Mar-Kel is the "same" size as the FonkenPrime (PrimeSize). There is also a mMar-Kel which is millSize. the "d" in dMar-Ken stands for deci and is one size down (deciSized)... for more detail on where & what the names of all the miniOnkens mean...http://www.diyaudio.com/forums/plane...ose-names.html